OCEANPORT -- It was supposed to be the first of its kind in New Jersey: a lounge at Monmouth Park racetrack where people could legally bet on sports games -- just like they do in Las Vegas.

Four years after it was built, not a single bet has been placed. The lounge at the Oceanport track has been operating as a sports bar instead as the state's effort to legalize sports betting at racetracks and casinos has been held up in a lengthy court battle.

But that could soon change. The U.S. Supreme Court is scheduled to hear oral arguments in the case Dec. 4, and experts and officials say the scales finally appear to be tipping in New Jersey's favor.

"Anybody watching from the sidelines can see the writing on the wall," said Daniel Wallach, a gaming and sports law attorney with Becker & Poliakoff in Fort Lauderdale, Florida.

A ruling is not expected for months after the arguments -- likely in the spring, possibly as late as June.

But racetrack and casino operators are so confident that they're already making preparations.

Monmouth Park CEO Dennis Drazin said the sports betting lounge -- a $1 million partnership with British bookmaker William Hill -- could be up and running with kiosks and tellers within weeks after the decision.

Drazin said there are also plans to expand the lounge it into the grandstand and open a full-scale Las Vegas-style sportsbook.

Eighty miles south, MGM announced last week that it will soon begin construction on a $7 million sportsbook at the Borgata casino in Atlantic City. And more casinos are likely to follow.

"The Atlantic City casinos can't wait until April to get their plans in order," Wallach said. "They have to prepare now. This controversy is rounding third base right now. It's almost over."

Of course, none of this is a sure bet. After New Jersey voters approved sports betting in a 2011 referendum, a group of college and professional sports leagues -- the NCAA, NFL, NBA, MLB, and NHL -- successfully sued to stop Gov. Chris Christie's administration from implementing it.

Their argument: Not only does sports betting hurt the integrity of their games, it also violates the 1992 Professional and Amateur Sports Protection Act, which bans such wagering in all but four states.

A number of courts have ruled against New Jersey. But the Supreme Court unexpectedly took up the case, even after the U.S. solicitor general in President Donald Trump's administration advised the court to pass on it.

State Sen. Raymond Lesniak, D-Union, who has spent years pushing for sports betting in New Jersey, said the nation's highest court "sent a clear message" by ignoring the solicitor general.

"I don't believe they would have done that only to knock it down," Lesniak said.

Thus, experts say, the court could decide to overturn the federal ban completely. And that could spur a slew of other states to legalize sports betting. Eighteen states have filed briefs in support of New Jersey's case.

Bill Pascrell III, a lobbyist who has also spent years on the fight, said it helps that Trump recently appointed Neil Gorsuch to the court because Gorsuch is an advocate for states' rights.

But Wallach said it's more likely the court will allow New Jersey to institute its latest plan: to repeal state laws banning sports betting to permit the wagering at racetracks and casinos.

That means there would be no state regulation. The tracks and casinos would create their own regulatory process instead.

Such a scenario, Wallach said, would likely "carve out an East Coast monopoly (on sports betting) for New Jersey until Congress changes the landscape."

That, he said, is because other states might think twice should that ruling occur.

"You're talking about a state repealing criminal prohibitions governing sports betting," Wallach said. "Who else besides New Jersey would be willing to do that?"

And if the court sides with the sports leagues? U.S. Rep. Frank Pallone, D-11th Dist., said he's already drafted a bill that would overturn the federal ban and allow states to set up sports betting and online gambling if they choose, as long as it's regulated.

For that to become law, Pallone would need Congress to approve it and Trump to sign it.

But Pallone said his colleagues are "coming on board more" than they used to on this issue.

Proponents' main argument is that sports betting is already taking place in the U.S. illegally, often run by organized crime.

Americans bet up to $60 billion annual on sports via offshore websites and bookmakers, according to Eilers & Krejcik Gaming. Others estimate the underground industry is worth more than $150 billion a year.

Drazin said that money could give a serious boost to New Jersey's horse-racing industry, which has been struggling in recent years after losing state subsidies.

"Sports betting for us is survival here at Monmouth Park," the track's CEO said.

Atlantic City has also struggled in recent years, thanks in part to a string of casinos closing.

Whatever happens, the ruling will likely occur after Christie, a major proponent of sports betting, leaves the governor's office Jan. 16. But Pascrell, the lobbyist, said incoming governor Phil Murphy is also on board.

Murphy's spokesman did not immediately return a message seeking comment.

"This has been a long, long road," Pascrell said. "But I have never been more confident of the outcome. The stars are aligned."